HSBoundaryRadiation

This component is a heat structure boundary that applies radiative heat transfer boundary conditions.

Usage

The parameter "hs" specifies the name of the heat structure component, and "boundary" is a list of boundary names on the heat structure where the boundary condition is to be applied.

The parameter "T_ambient" gives the ambient temperature TT_\infty, "emissivity" gives the surface emissivity ϵ\epsilon, and "view_factor" gives the view factor FF.

The parameter "scale_pp" specifies the name of a post-processor ff that can scale the boundary conditions.

Input Parameters

  • T_ambientTemperature of environment [K]

    C++ Type:FunctionName

    Unit:(no unit assumed)

    Controllable:No

    Description:Temperature of environment [K]

  • boundaryList of boundary names for which this component applies

    C++ Type:std::vector<BoundaryName>

    Unit:(no unit assumed)

    Controllable:No

    Description:List of boundary names for which this component applies

  • emissivityEmissivity of flow channel [-]

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Emissivity of flow channel [-]

  • hsHeat structure name

    C++ Type:std::string

    Unit:(no unit assumed)

    Controllable:No

    Description:Heat structure name

Required Parameters

  • scale1Function by which to scale the boundary condition

    Default:1

    C++ Type:FunctionName

    Unit:(no unit assumed)

    Controllable:No

    Description:Function by which to scale the boundary condition

  • scale_heat_rate_ppTrueIf true, the scaling function is applied to the heat rate post-processor.

    Default:True

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:If true, the scaling function is applied to the heat rate post-processor.

  • view_factor1View factor function [-]

    Default:1

    C++ Type:FunctionName

    Unit:(no unit assumed)

    Controllable:No

    Description:View factor function [-]

Optional Parameters

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector<std::string>

    Unit:(no unit assumed)

    Controllable:No

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:Set the enabled status of the MooseObject.

If this component is used with a cylindrical heat structure, the post-processor name_integral is added, which gives the heat rate found by integrating this heat flux over the boundary.

Advanced Parameters

Formulation

The heat conduction equation is the following: ρcp\pdTt(kT)=q\eqc \rho c_p \pd{T}{t} - \nabla \cdot (k \nabla T) = q''' \eqc where

  • ρ\rho is density,

  • cpc_p is specific heat capacity,

  • kk is thermal conductivity,

  • TT is temperature, and

  • qq''' is a volumetric heat source.

Multiplying by a test function ϕi\phi_i and integrating by parts over the domain Ω\Omega gives \prρcp\pdTt,ϕiΩ+\prkT,ϕiΩkT,ϕinΩ=\prq,ϕiΩ\eqc \pr{\rho c_p \pd{T}{t}, \phi_i}_\Omega + \pr{k \nabla T, \nabla\phi_i}_\Omega - \left\langle k \nabla T, \phi_i\mathbf{n}\right\rangle_{\partial\Omega} = \pr{q''', \phi_i}_\Omega \eqc where Ω\partial\Omega is the boundary of the domain Ω\Omega.

For Neumann boundary conditions on the boundary Γ\Gamma, kTnk \nabla T \cdot \mathbf{n} is replaced with a known incoming heat flux function qbq_b:

kTn=qbxΓ\eqpk \nabla T \cdot \mathbf{n} = q_b \qquad \mathbf{x} \in \Gamma \eqp

For radiation boundary conditions, the incoming boundary heat flux qbq_b is computed as

qb=fσϵF(T4T4)\eqc q_b = f \sigma \epsilon F (T^4_\infty - T^4) \eqc where

  • σ\sigma is the Stefan-Boltzmann constant,

  • ϵ\epsilon is the emissivity of the surface,

  • FF is the view factor function,

  • TT is the temperature of the surface,

  • TT_\infty is the ambient temperature, and

  • ff is an optional scaling factor.